Home / Examples / Thermal Analysis [Watt] / Example 24: Thermal Analysis Using Results (Heat Density) Imported from Magnetic Field Harmonic Analysis

Example 24: Thermal Analysis Using Results (Heat Density) Imported from Electric-Harmonic Analysis

General

• The loss density imported from the electric-harmonic analysis is used for the thermal analysis.
   

• The temperature distribution and the heat flux vectors are solved.
   

• Unless specified in the list below, the default conditions will be applied.

 

• Obtain this session's project file. (Right-click and choose 'Save link as')




• Results will vary depending on Femtet version and the PC environment.

 

Analysis Conditions

Item	Setting
Solver	Thermal Analysis [Watt]
Analysis Space	3D
Analysis Type	Steady-state Analysis
Unit	mm
Results Import	Heat Density

Model

The board is a rectangular solid body.
The strip line is a sheet body created on the surface of the board.

 

Body Attributes and Materials

Body Number/Type	Body Attribute Name	Material Name
0/Solid	VOL1	001_Alumina *
6/Sheet	VOL2	008_Cu (*)

* Available from the material DB

 

The conductive strip line is a sheet body. Its thickness must be defined.

The values of current and heat quantity will vary depending on the thickness.

Body Attribute Name	Thickness/Width	Analysis Domain
StripLine	Thickness of Sheet Body : 0.1mm

 

Boundary Condition

• The temperature of the bottom face of the substrate is set to 25 [deg] by the boundary condition of T0.

• The faces where the strip line ends are set with the [Adiabatic] boundary condition, T_Wall.
  Accordingly, the outer boundary condition, as stated below, will not be applied to the faces.

• The heat transfer to the ambient is defined by the outer boundary condition.

 

Boundary Condition Name/Topology	Tab	Boundary Condition Type	Setting
T_Wall/Face	Thermal	Adiabatic
T0/Face	Thermal	Temperature	25 [deg]
Outer Boundary Condition *	Thermal	Heat Transfer/Convection	Coefficient of Heat Transfer: 10 [W/m2/deg] Ambient Temperature: 25 [deg]

 

Results

First, run the electric analysis in the project. The loss density diagram is shown below.

You can see the current density is distributed around the bending area of the strip.

 

Next, run the thermal analysis in the project. The diagram below shows the temperature distribution.

Temperature rise due to heat generation occurs along the strip line, and the heat is transmitted to the alumina substrate.